急性脊髓损伤后促红细胞生成素受体的表达及其意义

目的探讨急性脊髓损伤后促红细胞生成素(EPO)及其受体(EPO-R)在脊髓内的表达。方法Wistar大鼠69只,随机分为三组：正常对照组(5只,不手术,作为后两组的对照)、假手术组(仅行椎板切除术)和脊髓损伤组。根据术后时间点不同后两组又分为1h、6h、12h、24h、3d、7d、14d和28d八个亚组(每组4只)。采用RT-PCR、Western blot免疫印迹法和免疫组织化学染色法检测EPO及EPO-R的表达。结果正常对照组、假手术组和脊髓损伤组在各时相点均未发现有EPO表达。正常对照组、假手术组未发现EPO-R的表达,脊髓损伤组在伤后1h未见EPO-R mRNA和蛋白的表达,6h开始有表达,12h有明显的表达,至24h达到高峰,3d和7d时仍维持在高表达水平,未见减弱,14d开始下降,至28d时仍有EPO-R蛋白的表达。免疫组化显示EPO-R阳性细胞主要位于神经元、少突胶质细胞、血管内皮细胞和脊髓中央管内室管膜细胞。结论大鼠急性脊髓损伤后脊髓内大量表达EPO-R,这是外源性EPO与EPO-R结合产生神经保护作用的分子基础。

The expression of erythropoietin receptor in the spinal cord after acute traumatic injury in adult rats

Objective To investigate the expressions of erythropoietin(EPO)and its receptor(EPO-R)in the spinal cord after acute traumatic injury in adult rats.Methods Sixty-nine Wistar rats were randomly divided into three groups:normal control group(n=5),spinal cord injury group(n=32),and sham operation group(n= 32).The injury group and sham operation group were further randomly divided into eight subgroups respectively (n=4)(1h,6h,12h,24h,3d,7d,14d,28 dafter operation).The expressions of EPO and EPO-R at different time points were detected by RT-PCR,Western blot and immunohistochemical staining.Results EPO was nut detected at any time point in the normal control grnup,spinal cord injury group or sham operation group.The EPO-R expression was not found in the normal control group or sham operation group.RT-PCR and Western blot analyses revealed EPO-R mRNA and protein expressions in the injury group as early as 6 h after injury.The EPO-R mRNA and protein expressions sharply increased at 12 h,peaked at 24 h to 7 d,and gradually declined after 7 d. They were still higher than those in the control rats 28 d after injury.The EPO-R immunoreactivity was chiefly found in neurons,oligodendrocytes,vascular endothelial and ependymal cells.Conclusion The EPO-R expression can be up-regulated obviously in the injured spinal cord,which provides a molecular basis for the nerooprotection of exogenous EPO.